ICD-10 Code C84.A9 – Cutaneous T-cell lymphoma, unspecified, extranodal and solid organ sites (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C84.A9 – Cutaneous T-cell lymphoma, unspecified, extranodal and solid organ sites
What it is
This code identifies cutaneous T-cell lymphoma when the record does not specify the exact subtype, and the disease involves extranodal or solid organ sites. Use it when documentation confirms this lymphoma but does not name a more specific category.
Clinical signs
Clinical features vary; refer to documentation. Common findings in cutaneous T-cell lymphoma include persistent skin lesions, plaques, patches, or tumors, and pathology may support a T-cell lymphoma diagnosis.
When to use this code
Use this code when the provider documents cutaneous T-cell lymphoma and specifies extranodal or solid organ involvement, but the subtype remains unspecified. It is appropriate when notes, pathology, or oncology records support the diagnosis without further classification.
If the chart names a more specific cutaneous T-cell lymphoma type, code that diagnosis instead. Check documentation when the site of disease or lymphoma subtype is unclear.
Do not use for
Do not use this code for a clearly specified cutaneous T-cell lymphoma subtype or for skin-only disease without extranodal or solid organ involvement. Check documentation if the record suggests another lymphoma class.
Coding tip
Code the most specific lymphoma type and site documented; if the subtype is missing, confirm that extranodal or solid organ involvement is explicitly stated.